Stainless Steel (SS) Pipes are essential in industries requiring corrosion resistance, hygiene, and durability—such as chemical processing, food and beverage, pharmaceuticals, and oil and gas. Selecting the correct pipe size, schedule, and weight is critical for system performance, safety, and cost control.
This article provides a complete reference for stainless steel pipe dimensions, covering seamless and welded pipe types, in both metric (mm) and imperial (inch) units. All dimensional data follows ASME/ANSI B36.19, the standard for stainless steel pipe dimensions. (For a detailed comparison of manufacturing methods, ▶ see our guide: ERW vs Seamless Stainless Steel Pipe.)
To select the right stainless steel pipe:
1. Determine Size: Choose the required Nominal Pipe Size (NPS) or DN based on your flow and system design.3. Verify Standards: Confirm the material meets ASTM A312 requirements and that the tolerances are acceptable for your application.
| Nominal Bore (NB) | Outside Diameter (mm) | Sch-5S | Sch-10S | Sch-40S | Sch-80S | Sch-160S | Sch-XXS | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| mm | inch | WT (mm) | Weight (Kg/m) | WT (mm) | Weight (Kg/m) | WT (mm) | Weight (Kg/m) | WT (mm) | Weight (Kg/m) | WT (mm) | Weight (Kg/m) | WT (mm) | Weight (Kg/m) | |
| 3 | 1/8 | 10.3 | 1.24 | 0.276 | 1.24 | 0.28 | 1.73 | 0.37 | 2.41 | 0.47 | - | - | - | - |
| 6 | 1/4 | 13.7 | 1.24 | 0.390 | 1.65 | 0.49 | 2.24 | 0.631 | 3.02 | 0.80 | - | - | - | - |
| 10 | 3/8 | 17.1 | 1.24 | 0.490 | 1.65 | 0.63 | 2.31 | 0.845 | 3.20 | 1.10 | - | - | - | - |
| 15 | 1/2 | 21.3 | 1.65 | 0.800 | 2.11 | 1.00 | 2.77 | 1.27 | 3.75 | 1.62 | 4.75 | 1.94 | 7.47 | 2.55 |
| 20 | 3/4 | 26.7 | 1.65 | 1.03 | 2.11 | 1.28 | 2.87 | 1.68 | 3.91 | 2.20 | 5.54 | 2.89 | 7.82 | 3.63 |
| 25 | 1 | 33.4 | 1.65 | 1.30 | 2.77 | 2.09 | 3.38 | 2.50 | 4.55 | 3.24 | 6.35 | 4.24 | 9.09 | 5.45 |
| 32 | 1 1/4 | 42.2 | 1.65 | 1.65 | 2.77 | 2.70 | 3.56 | 3.38 | 4.85 | 4.47 | 6.35 | 5.61 | 9.70 | 7.77 |
| 40 | 1 1/2 | 48.3 | 1.65 | 1.91 | 2.77 | 3.11 | 3.68 | 4.05 | 5.08 | 5.41 | 7.14 | 7.25 | 10.16 | 9.54 |
| 50 | 2 | 60.3 | 1.65 | 2.40 | 2.77 | 3.93 | 3.91 | 5.44 | 5.54 | 7.48 | 8.74 | 11.1 | 11.07 | 13.44 |
| 65 | 2 1/2 | 73.0 | 2.11 | 3.69 | 3.05 | 5.26 | 5.16 | 8.63 | 7.01 | 11.4 | 9.53 | 14.9 | 14.2 | 20.39 |
| 80 | 3 | 88.9 | 2.11 | 4.51 | 3.05 | 6.45 | 5.49 | 11.30 | 7.62 | 15.2 | 11.1 | 21.3 | 15.24 | 27.65 |
| 100 | 4 | 114.3 | 2.11 | 5.84 | 3.05 | 8.36 | 6.02 | 16.07 | 8.56 | 22.3 | 13.49 | 33.54 | 17.12 | 41.03 |
| 125 | 5 | 141.3 | 2.77 | 9.47 | 3.40 | 11.57 | 6.55 | 21.8 | 9.53 | 31.97 | 15.88 | 49.11 | 19.05 | 57.43 |
| 150 | 6 | 168.3 | 2.77 | 11.32 | 3.40 | 13.84 | 7.11 | 28.3 | 10.97 | 42.7 | 18.2 | 67.56 | 21.95 | 79.22 |
| 200 | 8 | 219.1 | 2.77 | 14.79 | 3.76 | 19.96 | 8.18 | 42.6 | 12.7 | 64.6 | 23.0 | 111.2 | 22.23 | 107.8 |
| 250 | 10 | 273.1 | 3.40 | 22.63 | 4.19 | 27.78 | 9.27 | 60.5 | 12.7 | 96.0 | 28.6 | 172.4 | 25.40 | 155.15 |
| 300 | 12 | 323.9 | 3.96 | 31.25 | 4.57 | 36.00 | 9.52 | 73.88 | 12.7 | 132.0 | 33.32 | 238.76 | 25.40 | 186.97 |
| 350 | 14 | 355.6 | 3.96 | 34.36 | 4.78 | 41.3 | 11.13 | 94.59 | 19.05 | 158.08 | 35.71 | 281.70 | - | - |
| 400 | 16 | 406.4 | 4.19 | 41.56 | 4.78 | 47.29 | 12.7 | 123.30 | 21.41 | 203.33 | 40.46 | 365.11 | - | - |
| 450 | 18 | 457.2 | 4.19 | 46.80 | 4.78 | 53.42 | 14.27 | 155.80 | 23.8 | 254.36 | 45.71 | 466.40 | - | - |
| 500 | 20 | 508.0 | 4.78 | 59.25 | 5.54 | 68.71 | 15.09 | 183.42 | 26.19 | 311.2 | 49.99 | 564.68 | - | - |
| 600 | 24 | 609.6 | 5.54 | 82.47 | 6.35 | 94.45 | 17.48 | 255.41 | 30.96 | 442.08 | 59.54 | 808.22 | - | - |
This comprehensive schedule chart lists pipe sizes from 8" to 36" NPS, showing OD in inches and wall thickness (inches) / weight per foot (lb/ft) for schedules 5S through DBL E.H. (Double Extra Heavy).
| NPS (inch) | OD (in) | 5s | 5 | 10s | 10 | 20 | 30 | 40s & Std. | 40 | 60 | 80s & E.H. | 80 | 100 | 120 | 140 | 160 | DBL E.H. | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | WT | W | ||||
| 8 | 8.625 | .109 | 9.914 | .109 | 9.914 | .148 | 13.40 | .148 | 13.40 | .250 | 22.36 | .277 | 24.70 | .322 | 28.55 | .322 | 28.55 | .406 | 35.64 | .500 | 43.39 | .500 | 43.39 | .593 | 50.87 | .718 | 60.93 | .812 | 67.76 | .906 | 74.69 | .885 | 72.42 |
| 10 | 10.750 | .134 | 15.19 | .134 | 15.19 | .165 | 18.65 | .165 | 18.70 | .250 | 28.04 | .307 | 34.24 | .365 | 40.48 | .365 | 40.48 | .500 | 54.74 | .500 | 54.74 | .500 | 54.74 | .593 | 64.33 | .718 | 76.93 | .843 | 89.20 | 1.000 | 104.10 | 1.125 | 115.70 |
| 12 | 12.750 | .156 | 21.07 | .165 | 22.18 | .180 | 24.16 | .180 | 24.20 | .250 | 33.38 | .330 | 43.77 | .375 | 49.56 | .406 | 53.53 | .562 | 73.16 | .500 | 65.42 | .500 | 65.42 | .687 | 88.51 | .843 | 107.20 | 1.000 | 125.50 | 1.125 | 139.70 | 1.312 | 160.3 |
| 14 | 14.000 | .156 | 23.07 | - | - | .188 | 27.73 | - | - | .250 | 36.71 | .312 | 45.38 | .375 | 54.57 | .375 | 54.57 | .437 | 63.37 | .593 | 84.91 | .500 | 72.09 | .750 | 106.10 | .937 | 130.70 | 1.093 | 150.70 | 1.250 | 170.20 | 1.406 | 189.10 |
| 16 | 16.000 | .165 | 27.90 | - | - | .188 | 31.75 | - | - | .250 | 42.05 | .312 | 52.36 | .375 | 62.58 | .375 | 62.58 | .500 | 82.77 | .656 | 107.50 | .500 | 82.77 | .843 | 136.50 | 1.031 | 164.80 | 1.218 | 192.30 | 1.427 | 223.50 | 1.593 | 245.10 |
| 18 | 18.000 | .165 | 31.43 | - | - | .188 | 35.76 | - | - | .250 | 47.39 | .312 | 59.03 | .437 | 82.06 | .375 | 70.59 | .562 | 104.20 | .750 | 138.20 | .500 | 93.45 | .937 | 170.80 | 1.156 | 208.00 | 1.375 | 244.10 | 1.562 | 274.20 | 1.781 | 308.50 |
| 20 | 20.000 | - | - | .188 | 39.78 | - | - | .218 | 46.05 | .250 | 52.73 | .375 | 78.60 | .500 | 104.10 | .375 | 78.60 | .593 | 122.90 | .812 | 166.40 | .500 | 104.10 | 1.031 | 208.90 | 1.280 | 256.10 | 1.500 | 296.40 | 1.750 | 341.10 | 1.968 | 379.00 |
| 24 | 24.000 | - | - | .218 | 55.37 | - | - | .250 | 63.41 | .250 | 63.41 | .375 | 94.62 | .562 | 140.80 | .375 | 94.62 | .687 | 171.20 | .968 | 238.10 | .500 | 125.50 | 1.218 | 296.40 | 1.531 | 367.40 | 1.812 | 429.40 | 2.062 | 483.10 | 2.344 | 542.13 |
Note: Entries are shown as Wall Thickness (inches) / Weight (lb/ft). Data per ANSI B36.19 and related standards. “-” indicates schedule not available for that size.Note: Entries are shown as Wall Thickness (inches) / Weight (lb/ft). Data per ANSI B36.19 and related standards. “-” indicates schedule not available for that size.
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It is essential to understand that ASME B36.10 covers carbon and alloy steel pipe, while ASME B36.19 covers stainless steel pipe.
| NPS |
Sch 40S Stainless Steel (mm) |
Sch 40 Carbon Steel (mm) |
Difference |
| 10 | 9.27 | 12.70 |
–27% |
| 12 | 9.53 | 12.70 |
–25% |
| 14 | 9.53 | 12.70 |
–25% |
ASTM A312/A312M is the primary material specification for austenitic stainless steel pipe (Grades 304, 304L, 316, 316L, 321, 347, etc.) for high-temperature and corrosive service. It references ASME B36.19 for dimensions and also specifies tolerances.
| Grade | Type | Key Characteristics |
|---|---|---|
| TP304 / 304L | Austenitic | Most common; general corrosive service |
| TP304H | High-Temp | Modified TP304 for creep resistance |
| TP316 / 316L | Austenitic | Molybdenum added; better chloride resistance |
| TP316H | High-Temp | Modified TP316 for creep resistance |
| TP321 / 321H | Stabilized | Titanium-stabilized; good for welding |
| TP347 / 347H | Stabilized | Niobium-stabilized; high-temperature strength |
| TP309H / TP310H | High-Temp | Higher chromium/nickel; extreme heat resistance |
ASTM A312 covers seamless, welded, and heavily cold worked austenitic stainless steel pipe. The “H” grades (e.g., TP304H, TP316H, TP321H, TP347H) are modified for high-temperature service where creep and stress rupture properties are important.
| Dimension | Tolerance | Notes |
|---|---|---|
| Outside Diameter (OD) | Varies by size; typically ±0.031″ for 1-1/2″ to 4″ NPS | Tighter tolerances apply for smaller sizes under ASTM A269/A213 |
| Wall Thickness | Seamless: -12.5% under nominal wall thickness | Per ASME SA999 |
| Length | Random lengths normally ordered | Specific tolerances apply per ASTM A530 |
| Out-of-Roundness | Not to exceed specified limits | Varies by NPS |
This table summarizes allowable outside diameter and wall thickness variations, length tolerances, and required tests for key ASTM standards (A213, A249, A269, A270, A312, A358).
| Specification | Allowable Outside Diameter | Allowable Wall Thickness | Exact Length | Testing | ||||
|---|---|---|---|---|---|---|---|---|
| Nominal Diameter | Over | Under | %Over | %Under | Over | Under | ||
| Variation in mm | Thickness Variation | Tolerance in mm | ||||||
|
ASTM-A213 (Seamless Boiler, Superheater, Heat Exchanger Tubes) |
Under 25.4 | 0.1016 | 0.1016 | +20 | 0 | 3.175 | 0 | Tension Test |
| 25.4-38.1 incl | 0.1524 | 0.1524 | +22 | 0 | 3.175 | 0 | Flare Test | |
| 38.1-50.8 excl | 0.2032 | 0.2032 | +22 | 0 | 3.176 | 0 | Hardness Test | |
| 50.8-63.5 excl | 0.254 | 0.254 | +22 | 0 | 4.46 | 0 | ||
| 63.5-76.2 excl | 0.3048 | 0.3048 | +22 | 0 | 4.76 | 0 | 100% Hydrostatic test | |
| 76.2-101.6 incl | 0.381 | 0.381 | +22 | 0 | 4.76 | 0 | Refer to ASTM A-450 | |
|
ASTM-A249 (Welded Boiler, Superheater, Heat Exchanger, Condenser Tubes) |
Under 25.4 | 0.1016 | 0.1016 | +10 | -10 | 3.175 | 0 | |
| 25.4-38.1 incl | 0.1524 | 0.1524 | +10 | -10 | 3.175 | 0 | Tension Test | |
| 38.1-50.8 Excl | 0.2032 | 0.2032 | +10 | -10 | 3.175 | 0 | Flattening Test | |
| 50.0-63.5 excl | 0.254 | 0.254 | +10 | -10 | 4.762 | 0 | Flange Test | |
| 63.5-76.2 excl | 0.3848 | 0.3048 | +10 | -10 | 4.762 | 0 | Reverse Bend Test | |
| 76.2-101.6 incl | 0.381 | 0.381 | +10 | -10 | 4.762 | 0 | Hardness Test | |
|
ASTM-A249 (cont.) (Minimum Wall tubes) |
Minimum Wall tubes, + 18% 0 available, On request | 100% Hydrostastic Test | ||||||
| Refer to ASTM A-450 | ||||||||
|
ASTM-A269 (Seamless & Welded Tubing for General Service) |
Untp 12.7 | 0.13 | 0.13 | +15 | -15 | 3.2 | 0 | Flare Test (Seamless Only) |
| 12.7-38.1 excl | 0.13 | 0.13 | +10 | -10 | 3.2 | 0 | Flange Test (Welded Only) | |
| 38.1-88.9 excl | 0.25 | 0.25 | +10 | -10 | 4.8 | 0 | Hardness Test | |
| 88.9-139.7 excl | 0.38 | 0.38 | +10 | -10 | 4.8 | 0 | Reverse Flattening Test | |
| 139.7-203.2 excl | 0.76 | 0.76 | +10 | -10 | 4.8 | 0 | (Welded only) | |
| 100% Hydrostatic Test | ||||||||
| Refer to ASTM-A269 | ||||||||
|
ASTM-A270 (Seamless & Welded Sanitary Tubing) |
25.4 | 0.05 | 0.20 | +10.0 | -10.0 | 3.2 | 0 | |
| 38.1 | 0.05 | 0.20 | +10.0 | -10.0 | 3.2 | 0 | Reverse flattening Test | |
| 50.8 | 0.05 | 0.28 | +10.0 | -10.0 | 3.2 | 0 | 100% Hydrostastic Test | |
| 60.5 | 0.05 | 0.28 | +10.0 | -10.0 | 3.2 | 0 | External' polish on all tubes | |
| ASTM-A270 (cont.) | 76.2 | 0.08 | 0.30 | +10.0 | -10.0 | 3.2 | 0 | Refer to ASTM A-270 |
| 101.6 | 0.08 | 0.38 | +10.0 | -10.0 | 4.8 | 0 | ||
| 3.175-38.1 incl | 0.4 | 0.79 | Minimum Wall | 6.4 | 0 | |||
| 38.1-1016 incl | 0.79 | 0.79 | 12.5% under | 6.4 | 0 | Tension Test | ||
|
ASTM-A312 (Seamless & Welded Pipe) |
101.6-203.2 incl | 1.59 | 0.79 | nominal wall | 6.4 | 0 | Flattening Test | |
| Specified | 100% Hydrostatic Test | |||||||
| (Normally Random | Refer to ASTM A-530 | |||||||
|
ASTM-A358 (Welded pipe) |
219.08-750mm | +0.5% | -0.3 | 6.0 | Refer to ASTM A-530 | |||
This table provides the weight per meter for common imperial OD sizes based on standard gauge (SWG) wall thicknesses.
| Size (inch) | OD (mm) | Weight per Meter (Kg/m) by Gauge (SWG) | |||||
|---|---|---|---|---|---|---|---|
| 10 SWG (3.2 mm) | 12 SWG (2.6 mm) | 14 SWG (2.1 mm) | 16 SWG (1.65 mm) | 18 SWG (1.2 mm) | 19 SWG (1.0 mm) | ||
| 1/2" | 12.7 | 0.754 | 0.651 | 0.552 | 0.452 | 0.342 | 0.290 |
| 5/8" | 15.875 | 1.006 | 0.856 | 0.718 | 0.582 | 0.437 | 0.369 |
| 3/4" | 19.05 | 1.258 | 1.061 | 0.883 | 0.712 | 0.531 | 0.448 |
| 1" | 25.4 | 1.762 | 1.470 | 1.214 | 0.972 | 0.720 | 0.605 |
| 1 1/4" | 31.75 | 2.266 | 1.880 | 1.544 | 1.232 | 0.909 | 0.763 |
| 1 1/2" | 38.1 | 2.770 | 2.289 | 1.875 | 1.492 | 1.098 | 0.920 |
| 2" | 50.8 | 3.778 | 3.108 | 2.537 | 2.012 | 1.476 | 1.235 |
| 2 1/2" | 63.5 | 4.786 | 3.928 | 3.198 | 2.531 | 1.854 | 1.550 |
| 3" | 76.2 | 5.794 | 4.747 | 3.860 | 3.051 | 2.232 | 1.865 |
| 3 1/2" | 88.9 | 6.802 | 5.566 | 4.521 | 3.571 | 2.610 | 2.180 |
| 4" | 101.6 | 7.810 | 6.385 | 5.183 | 4.091 | 2.988 | 2.495 |
For special specifications, complex applications, or if you need a quote for custom sizes, please contact our technical support team.
Related Resources:
● How to Choose the Right Wall Thickness (Sch40 vs Sch80) for Your Application
● Seamless Steel Pipe Sizes and Weights
● ERW vs Seamless Stainless Steel Pipe: 6 Key Differences
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